The present invention relates to a charging apparatus suitable for use with a wireless device, and particularly to a charging apparatus suitable for use with a wireless device, which is capable of stopping the application of a voltage across power receiving terminals upon usage of the wireless device by a simple circuit configuration without a change in the sizes of the wireless device.
A manually-operated wireless device, e.g., a bar-code scanner for reading bar codes has heretofore utilized a battery incorporated therein as a power supply. Once the built-in battery wears, the bar-code scanner does not read each bar code with accuracy. Thus, when the bar-code scanner is not in use, i.e., when the reading of the bar code is not being performed by the bar-code scanner, the bar-code scanner is normally electrically connected to a charger so that the battery incorporated in the bar-code scanner is charged by charging power produced from the charger.
FIGS. 3A and 3B are a perspective view showing examples of configurations of an already-known bar-code scanner and a charger therefor. FIG. 3A illustrates one example of the configuration of the bar-code scanner and FIG. 3B shows one example of the configuration of the charger.
FIG. 4 shows a state in which the bar-code scanner shown in FIG. 3A has been connected to the charger shown in FIG. 3B, i.e., FIG. 4 is a perspective view illustrating one example of a configuration of a charging apparatus suitable for use with the known bar-code scanner.
As shown in FIG. 3A, the bar-code scanner 30 comprises a main body 31, a bar-code reader 32, a pair of power receiving terminals (not shown) mounted to the main body 31, and a built-in power battery (not shown). Upon operation of the bar-code scanner 30, the main body 31 is gripped with hand and the bar-code reader 32 is turned toward a bar code 32a. Thereafter, the bar-code reader 32 suitably scans over the bar code 32a to read the bar code 32a.
As illustrated in FIG. 3B, the charger 35 comprises a main body 36, a bar-code scanner placement portion 37 provided on the upper side of the main body 36, a pair of charging terminals 38 exposed to the bar-code scanner placement portion 37, a charging circuit portion 39 provided on the side of the main body 36, and a communication control unit 40 provided on the rear side of the main body 36. When the bar-code scanner 30 is placed in the bar-code scanner placement portion 37 as shown in FIG. 4, the pair of charging terminals 38 are respectively electrically brought into contact with the pair of power receiving terminals on the bar-code scanner 30 side so that charging power outputted from the charging circuit portion 39 serves so as to charge the built-in power battery of the bar-code scanner 30 through the charging terminals 38 and the power receiving terminals. In this case, the communication control unit 40 performs wireless communications with the bar-code scanner 30 and controls communications with a host computer (not shown).
The known charging apparatus suitable for use with the bar-code scanner has a problem in that since the pair of charging terminals 38 mounted to the bar-code scanner placement portion 37 on the charger 30 side projects from the bar-code scanner placement portion 37 upon reading the bar code 32a by the bar-code scanner 35, an operator or others do not experience an abrupt impact due to an electric shock when being accidentally placed in contact with the pair of charging terminals 38, and an electrical short occurs across the pair of charging terminals 38 when a foreign matter composed of a conductor is brought into contact with the pair of charging terminals 38.
In order to solve such a problem, a charging apparatus suitable for use with a bar-code scanner has already been proposed which is capable of stopping the supply of power to the pair of charging terminals 38 when the bar-code scanner 30 is not placed in the bar-code scanner placement portion 37, thereby preventing the occurrence of the abrupt impact and electrical short due to the electric shock. A charging apparatus suitable for use with a bar-code scanner, which has been disclosed in Japanese Patent Application Laid-Open No. 2-151231, is known as one example.
In the charging apparatus disclosed in Japanese Patent Application Laid-Open No. 2-151231, a lead switch is provided on the charger 35 side so as to be placed between a charging circuit portion 39 and a pair of charging terminals 38. Further, a magnet is disposed on the bar-code scanner 30 side. When the bar-code scanner 30 is placed in a bar-code scanner placement portion 37, the lead switch on the charger 30 side is closed under the supply of a magnetic field produced from the magnet on the bar-code scanner 30 side so as to connect the charging circuit portion 39 and the pair of charging terminals 38 to each other, whereby charging power is supplied to the pair of charging terminals 38. On the other hand, when the bar-code scanner 30 is not placed in the bar-code scanner placement portion 37, i.e., when the bar-code scanner 30 is used to read a bar code 32a, the supply of the magnetic field from the magnet on the bar-code scanner 30 side is interrupted so as to open the lead switch on the charger 30 side thereby to disconnect the charging circuit portion 39 from the pair of charging terminals 38, whereby the supply of the charging power to the pair of charging terminals 38 is stopped.
Since the supply of the charging power to the pair of charging terminals 38 on the charger 35 side is stopped when the bar-code scanner 30 is not placed in the bar-code scanner placement portion 37, i.e., the reading of the bar code 32a by the bar-code scanner 30 is being performed, the charging apparatus disclosed in Japanese Patent Application Laid-Open No. 2-151231 can prevent the abrupt impact and the electrical short from occurring on the charger 35 side due to the electric shock.
However, the charging apparatus referred to above has a new problem in that since a voltage produced from a built-in power battery remains applied to a pair of power receiving terminals exposed on the bar-code scanner 30 side, an operator of the bar-code scanner 30 will experience an abrupt impact due to an electric shock when the operator accidentally makes contact with the pair of power receiving terminals.
Further, the above-described charging apparatus has a further new problem in that since it is quite common that a conductive material such as waterdrops or the like is attached to each of products if considering where the charger 35 doubles as a terminal device of a POS system and each of bar codes marked on the products is read by the bar-code scanner 30, the exposed pair of power receiving terminals is electrically short-circuited by the conductive material such as the waterdrops, so that the power battery incorporated into the bar-code scanner 30 is suddenly used up.